Cloning and identification of a novel binding protein of CD2 cytoplasmic domain

In order to understand why CD2 has a dual action of transduction of activat ion or apoptosis signals in T cells under different experimental conditions , we employed a yeast two-hybrid system to look for a binding protein of th e cytoplasmic domain of CD2 which may be involved in this issue. A human T cell cDNA library was screened by a cDNA encoding the cytoplasmic domain of CD2 (Thr211-Gln336). The specificity of protein-protein interaction was ve rified by co-immunoprecipitation. The binding protein obtained, designated CD2cBP, was found to be homologous to v-fos transformation effector protein (Fte-1). As Fte-1 plays a role in cell transformation, growth, protein syn thesis and protein-import into mitochondria, this result suggests that CD2c BP may be putatively involved in CD2-mediated signaling.